Calreticulin–CD91 complex (CRT–CD91 complex)

The Calreticulin–CD91 complex is formed when calreticulin, a chaperone protein that can translocate to the cell surface, binds to CD91 (LRP1), a transmembrane endocytic receptor on phagocytic cells. Calreticulin acts as an "eat me" signal on apoptotic or stressed cells, and CD91 serves as the receptor that recognizes this signal, facilitating the uptake (macropinocytosis) and clearance of dying cells. This interaction is crucial for tissue homeostasis, immune surveillance, resolution of inflammation, and the immunogenicity of some forms of cell death (especially in cancer). Disruption or dysregulation of this complex may contribute to diseases such as cancer and autoimmune disorders. While abundant data describe both calreticulin and CD91 individually, most mechanistic and disease associations reference their functional interplay rather than a distinct structural complex. The nomenclature "Calreticulin–CD91 complex" is valid for describing the ligand–receptor mechanism mediating clearance of dying cells, particularly in cancer immunology and tolerogenic pathways.

Other names

Calreticulin–CD91 receptor complexCRT–CD91 complexCalreticulin–LRP1 complexcC1qR–CD91 complex

Promotion of immunogenic cell death via surface exposure of calreticulin, which is then recognized by CD91 on phagocytic cells, triggering engulfment and cross-presentation of dying cell antigens. Stimulation of macropinocytosis through the ligation of calreticulin and CD91.